I just did a complete revamp of my "new" 98 SMB's stereo and related electronics. While nothing I did was terribly novel, maybe some of the things I did might help others who embark on a similar job. I have a 1998 Ford EB E250 that had the stock Ford cassette stereo and speakers in the front doors, side barn door, and rear doors.
I installed a new Kenwood double-DIN DVD headunit, Boyo rear camera, updated all the speakers, moved the rear speakers to the rear cabinets from the rear doors, and added an on/off switch for the speaker in the side barn door. Here are some thoughts:
1. Moved rear speakers to the rear cabinets: as others have noted, the speakers in the rear doors are not very effective as they are often blocked by the rear cabinets. We have an EB van with two full-height cabinets, so I moved the speakers to the cabinets. I removed the shot 6x8 speakers in the rear doors and tapped into the speaker wiring in the area behind the taillights, running the wiring into the van via the body holes (I left the original wire harnesses in the rear doors but removed the speakers). The 6.5" speakers I installed don't take up too much room inside the cabinet and were easy to install (plus, I've had them in a box in my basement for years so they were "free"). They sound a LOT better. As an aside, when I took the panels off the rear doors to remove the stock speakers, I found that there was a power door-lock switch back there hidden behind the panel, which SMB decided not to put in the panel (or forgot). I cut a hole in the rear door panel and it's really convenient to have a lock/unlock button there now for the whole van. If your van has power locks but doesn't have this switch visible in the rear door, I bet it's there and just hidden!
2. The speaker in the side barn door was also shot, so I replaced that with a 6x8 Sony speaker that I got cheap at a yard sale. While in there, I added a simple rocker switch to the negative speaker wire to make it easy to turn just that speaker on and off (since the side speaker is wired in parallel with the rear speakers, there is no way to turn it off via the fader function). I added the switch for two reasons: my young son sits in a third captain's chair right next to it, so I thought it might be handy to turn it off on occasion for him; also, when at camp, it's nice to leave the side doors open for airflow, but this faces the speaker out and could annoy neighbors if listening to the stereo inside the van.
3. Rear-view camera: I went with a mid-range camera from Boyo (http://www.amazon.com/gp/product/B0036D ... 04_s00_i01
) and mounted it in the license-plate area. The quality is pretty good, but not as good as the OEM one in my Honda Odyssey. I still need to play around with the placement to get it dialed-in. I had a bunch of coax cable laying around, so I used that to run the video from the camera to the stereo headunit in the dash. The coax was easy to run, is very sturdy, and I could add the connectors after I did all the fishing of the wire. I installed F connectors and then an F-to-RCA plug to hook up to the camera and stereo. I tapped into the backup lights in the rear of the van for the power, but I wish I would have run a switched power wire from the dash so I could turn on the camera at will, not just when backing up. I may still do this, but it would have been a lot easier to run the type of coax that also has power wires in it too.
4. Made fake faceplate to hide new DVD stereo: see the separate posting at viewtopic.php?f=14&t=9375